1. Field of the Invention
The present invention relates to a device and a method for controlling power to a vehicular differential speed controller and, more particularly, to a device and a method for maintaining power to a vehicular differential speed controller according to a parking brake signal.
2. Description of the Related Art
With reference to FIG. 7, for a vehicle equipped with differentials, such as an all-terrain vehicle, a front-wheel differential 801 and a rear-wheel differential 802 are provided and respectively controlled by a front differential speed controller 704 and a rear differential speed controller 705 at an unlocked state or a locked state.
When the front-wheel differential 801 and the rear-wheel differential 802 are at the unlocked state, the wheels on the left and right of the vehicle can be rotated at different speeds. On the other hand, when the front-wheel differential 801 and the rear-wheel differential 802 are at the locked state, the wheels on the left and right of the vehicle can be rotated at a same speed or synchronously rotated.
When the driver parks the vehicle and pulls the parking brake lever 703, the drive shaft connected to the wheels is locked to prevent the drive shaft from rotating. As to the control over the front-wheel differential 801 and the rear-wheel differential 802, the front differential speed controller 704 and the rear differential speed controller 705 acquire operating power from a vehicle power supply through a power switch 702. If the driver switches off the power switch 702, the front differential speed controller 704 and the rear differential speed controller immediately stop operation and are kept at the last operating state thereof before the power switch 702 is switched off. Hence, the front-wheel differential 201 and the rear-wheel differential 802 may still be maintained at the unlocked state.
As a result of the unlocked state of the front-wheel differential 801 and the rear-wheel differential 802, the wheels on the right and left of the vehicle can still be rotated. Under the circumstance of certain particular terrains, such as sloped hill, although the parking brake is pulled and the drive shaft is locked, the vehicle may be put in peril of accident due to vehicle movement arising from the rotating wheels.